creating a user with ssh access in unix

gistfile1.sh

# create a group for the new user
groupadd shreyansgroup

# create user, -d = home directory, -g = group, -s = default shell
# note, this will not create the home directory
useradd -d /home/shreyans -g shreyansgroup -s /bin/bash shreyans

# create home directory and assign it to the user
mkdir /home/shreyans
chown shreyansgroup:shreyans /home/shreyans

# switch to the user
sudo su shreyans

# set up ssh for the user
cd /home/shreyans
mkdir ~/.ssh
chmod 700 ~/.ssh
ssh-keygen -t rsa # creates an ssh key for the user. suppose it is named id_rsa (the default)
cd ~/.ssh
touch authorized_keys
cat id_rsa.pub >> authorized_keys

# now, get the private key to another computer somehow...
# then on the other computer:
chmod 400 ~/.ssh/id_rsa
ssh-add ~/.ssh/id_rsa

# log in!
ssh shreyans@server.com